Illinois Railway Museum Blog

IRM has accumulated overhead parts from everywhere over the years.  A small amount are old but never used but most are old used parts.  Many are styles that are no longer made and therefore have historical value.  A good example are wood strain insulators (wood strains).  This is one item we have in abundance, in varying conditions from never installed-still-in-the-box to outside rotting in a barrel.

Wood strains are insulating tension members installed in span wire to electrically insulate two sections of span wire or hardware and span wire.  They are also used as insulation between pieces of hardware and in specialwork.  They come in various sizes, lengths and end fitting configurations. The typical woodstrain is made of a section of turned hardwood rod with a mallable iron end fitting crimped on each end (eye-eye, clevis-eye etc.).  The modern equivelant uses fiberglass rod instead of wood.  Because of the wood which will rot, woodstrains are a high maintenance item.  Because of this, my policy is to recondition used woodstrains before putting them in service.  I have spent many weeks reconditioning parts to build up an inventory.

First, they are stripped of bolts, pins and wire.  Then, they are inspected for soundness.  After passing inspection the metal ends are sand blasted to white metal.  The wood is lightly sand blasted to remove loose paint and foreign matter.  After another inspection, the end fittings are dipped in cold galvanizing compound and allowed to dry.  One end must be dry before dipping the other end.  Next, two coats of grey oil base house paint are applied to the wood.  Once the paint has thoroughly dried the metal ends are given a final dip in galva-bright.  Now they not only look like(better than) new, but will last for years.  This process takes six days per batch (20-25 pcs). 

Other parts are reconditioned in a similar fashion.  Round top and pulloff hangers that have durego or composition insulation have the exposed insulation sand blasted and are given one coat of insulating varnish.  These are also dielectric tested to ensure insulation integrity.

Woodstrain before sandblasting

Woodstrain ends dipped in cold galvanize

Woodstrain ready for instalation